Air launched radio station



June 5, 1951 v BENNETT 2,555,867

AIR LAUNCHED RADIO STATION (7 Filed Aug. 28, 1945 3 Sheets-Sheet 1 3 wumm R BENNETT FIG, ROMBE T P R. P. BENNETT AIR LAUNCHED RADIO STATIONJune 5, 1951 3 Sheets-Sheet 2 Filed Apg. 28, 1945 O. 1 mo. mo. 7 1.1 Om

%% OMWVAM June 5, 195] R. P. BENNETT 2,555,867

AIR LAUNCHED RADIO STATION.

Filed Aug. 28, 1945 3 Sheets-Sheet 5 Igll/IIIIIIA VIIIIIII/I/I/l RQBERTBENNETT Patented June 5, 1951 UNITED STATES PATENT OFFICE AIR LAUNCHEDRADIO STATION Robert P. Bennett, White Hall, Md., assignor, by mesneassignments, to the United States of America Application August 28,1945, Serial No. 613,151

\ .mote or hostile territory.

In general, my invention resides in improvements of the air-launchedradio station disclosed I and claimed in copending application Ser.#600,- 621, filed June 20, 1945, by Percival D. Lowell et a1.

' More particularly, the erection of the station to suitable operatingposition subsequent to its fall to earth is made more certain by one, orthe other, preferably both of the following: mounting of the heaviercomponents as close as possible to the nose of the station housing toprovide low center of gravity and use of stationerecting legs which havegreat rotational in- 'ertia.

Also in accordance with my invention, the periods of transmission of thestation are predetermined, as by a clock-controlled master switch, tofacilitate reception from a number of such stations without mutualinterference.

Further in accordance with my invention, interrlocli switches areutilized to ensure release of 1"" a the parachute and actuation of theerecting legs in proper sequence.

In accordance with another aspect of my invention, the mounting for thetelescopic antenna of the station enables axial extension of the an-'tenna upon deformation of the nose portion of the station housing.

My invention also resides in features of construction,.combination andarrangement herein described or disclosed.

Referring to the drawings:

Figure 1 is a general sectional view showing the construction of thehousing and the location of theffmajor components.

Figure 2 is a circuit diagram of the apparatus mounted within thehousing shown in Figure 1 and shows circuit connections between thetiming device, the relaxation oscillator, and the radio transmitter.

Figure 3 is a sectional view taken on section 3-3 of Figure '7 and showsthe arming pin and associated switch.

Figure 4, a sectional view taken on section 4--4 of Figure 1, shows theexplosive release device for the parachute together with associatedswitches.

Figure 5, a sectional View taken on section 5-5 of Figure '7, shows theconstruction of the explosive release device utilized to release thelegs .prior to erection.

Figure 6 is an elevation view showing the degenerally by the numeral 10.cludes a main transverse member l2, a spider vice in erected positionwith legs and antenna extended.

Figure 7 is a plan view of the device shown in Figure 1, includingdetails of the leg-releasing means.

As shown in Figure 1, the complete assembly is similar in appearance toa bomb and because of its lighter weight is even more readilytransported by aircraft. The housing is indicated The housing in- M andan upper shelf member l6. These three members are connected bylongitudinal supporting members l8. A resiliently mounted shelf 20 issuspended from the transverse member l2 by shock supports 22. Above thetransverse member l2 are mounted the weather-responsive devicesconsisting of the pressure-responsive device 24, thetemperature-responsive device '26 and the humidity-responsive device 28.Mounted on the shelf 20 on the clock 30, the battery power supply 32,the relaxation oscillator 34and the radio transmitter 36.

Hingedly attached to the spider 14 are a plurality of legs 38 pivoted onpins 40. The legs 38 are spring-biased toward the nose portion 42 bymeans of powerful springs 44. The legs are held in the unerectedposition by means of retaining wires 46 held in place by the pin 92 ofthe explosive release device 48.

A yoke 56 is provided for carrying the station in a standard aircraftbomb-rack. After being released from an aircraft the device is supportedby means of a parachute, normally stored between the legs 38 in thespace 52, which limits rate of fall to approximately eight feet persec-- ond. The parachute supporting line 54 connects the parachute (notshown) to the supporting rod '56. The other end of the rod 56 engages aparachute release device 58 which is mounted at the spider [4 at a pointof great mechanical strength. Rod 56 is led into the interior of thestation through tube 60 which forms part of the vertical. supportingstructure. An arming switch 62 is attached to the parachute supportingline 54 by means of lead-line 64 and is released to apply battery powerto the nose switches 66 at the time that the parachute opens. Noseswitches 66 are effective to release the parachute when the weatherstation strikes the earth, through the operation of parachute releasedevice 58.

The nose 42 fastened to traverse member [2 is shaped so as to offerlitle resistance to motion through the air. The nose 42 is constructedof 3 thin deformable material such as light gauge metal and willnormally be deformed upon striking the earth. such deformation aids inprotecting the internal components from shock since the energy of impactis absorbed in the bending of the metal.

Mounted in close proximity to the inner surface of the nose 42 is avertical telescoping antenna 61, designed to operate by gas pressure,mounted in a barrel 68. Pressure to elevate the antenna is generated inthe explosive chamber erecting device connected to the antenna barrel 66by the flexible conduit 12. The antenna barrel 68 is slidably mounted inthe transverse member I2 and the spider member I4 in order to enableaxial translation of the antenna upon inward deformation of the nose 42.In Figure l the antenna barrel 66 is shown in contact with the innersurface of the nose 42. However, it will be obvious to one skilled inthe art that the antenna barrel need not actually be attached to thenose. The antenna and reservoir have been placed in the position shownin order that the center of gravity of the device may be as low aspossible and also to accommodate the length of the antenna, which isappreciable even when in the unerected position. Relative motion of thereservoir and the antenna barrel 68 upon impact is taken up in theflexible conduit 72.

The nose switches 66 are placed at spaced intervals about the nose sothat at least one switch is operated regardless of the angle at whichthe housing may strike the earth. The switches 66 are operated by theswitch operators 14 on the outside of nose 42.

Figure 3 is a sectional view of the arming switch 62, consisting merelyof a pin 16 normally housed in a bored hole 18. A single pole normallyclosed switch 80 closes the switch circuit upon the withdrawal of pin 16by lead line 64.

Figure 4 is a detailed sectional view of the parachute releasing device58. This device consists of a release pin 82, threading an eye on theend of rod 56. An explosive charge contained chamber 84 is fired by anelectric fusible resistance link (not shown) which is energized byterminal 86. Two normally-closed single pole switches 88 and 90 arereleased to make contact in two circuits upon the ejection of the pin82.

Figure 5 shows the explosive release device 48 which is similar inconstruction to that shown in Figure 4. It utilizes a pin 92 engagingthe leg releasing wires 46 and ejected by the explosive device 94. Theexplosive device contains a resistance firing element of a well knowntype not shown. A normally closed switch 96 and a normally open switch96, the use of which will be described below, are released upon ejectionof the in 92.

Figure 6 shows the weather station in the erected position as it appearsduring the transmission of a weather signal. Side panels I60 are shownto better advantage than in Figure 1. These are used to providemechanical protection and to offer better streamlining.

The electrical portion of the device shown in Figure 2 consists of anelectric clock of a well known type to control the erecting of thestation and the switching of weather-responsive resistances into thegrid circuit of a relaxation oscillator, relays to accomplish thisswitching, a relaxation oscillator and a transmitter controlled therebyas illustrated in Figure 2, the switches 80, 88, 90, 96, and 98 areshown in the positions in which they are maintained by the pins 16, 82,

and 92. These switches are positioned as shown at the beginning of theoperating cycle and are in each case changed upon ejection of theassociated pin by the operation of the fusible elements and 95. Theclock consists of a clock winding I02 operated by a clock battery I03, aclock minute hand I 04 and an hour hand I06. The hour hand controls fourcontacts I08 spaced at three hour intervals. The minute hand controlsterminals H0, H2, II4, H6, H8 and I20, controlling the operations to beperformed in sequence. Relay I22 operates the explosive leg releasingdevice 48. Relay I24 operates the antenna elevating device 10. Relay I26switches the pressure-responsive resistor into the relaxation oscillatorcircuit while relays I28 and I30 perform this function in the case ofthe temperature and humidity resistors respectively.

Numeral 24 indicates the pressure-responsive device consisting of avariable resistor I32 and the winding of a clamping device I34. Thetemperature-responsive device 26 includes a temperature-sensitiveresistor I36 while the humidity-responsive device includes a variableresistor I38 and the winding of a clamping device I40. The clampingdevices I34 and I46 are electromagnets which act to force the movingelement of the associated resistor into firmer contact with theresistance strips during-- the period of transmission. Numerals 13, 85and indicate the fusible resistance links controlling detonation of theexplosive devices associated with the parachute releasing device, theleg erecting device and the antenna erecting devices respectively.Fusible link 85 of a arachute release device is operated by noseswitches 66 in series with arming switch 80. Th fusible link 95 in theleg releasing device 46 is operated through contacts I08 and H0 of theclock 30 and contact 68 of the parachute release device 56. The fusiblelink 13 which sets off the explosive charge in the antenna erectingdevice 10 is energized by terminal II2 of the clock 30 and receivespower through switch 98 of the leg releasing device 48.

Power for the filaments of the vacuum tubes and the fusible links issupplied by battery I42, filament power being controlled by contacts I44associated with filament relay I46. Relay power is furnished from therelay battery I48. The contacts associated with the relays which aredesignated as I50, I52, I54, I56, I58, I60, I62 and I63, will bediscussed in describing the operation of the electrical portion of thedevice.

By the means of the clock 30, resistors I32, I36 and I38 and thereference resistor I 64 are applied successively on output terminals I66and I68. The latter terminals lead to the grid circuit of a relaxationoscillator 34. The relaxation oscillator includes a timing capacitorI16, vacuum tube I12, and grid-plate coupling transformer I14 whichoperates the plate circuit relay I16. The contacts I18 of this relayshort out resistor I86 supplying some of the grid bias in the crystaloscillator portion of the transmitter 36. This breaks the transmittedwave up .into pulses.

Operation of the parachute suspension line 54 applies ten.- sion-t'olead line 64 which-pulls the dowel 16 from the arming switch 62. Uponimpact with the ground, nose switch operators l4 actuate one or moreofthe switches 66 to make contact resulting in the release of theparachute by the operation of the parachute releasing device 58. Whenthe parachute pin 82 has been ejected from, the parachute releasemechanism 58, the switch 00 on. the :parachute releasing device appliesnegative voltage from the relay battery I48 to the hour hand contact I08of the clock 30. Atthe same time switch 90 on the parachute releasingdevice energizes the normally open contacts I50 of relay I22. Theweather station normally will lie on its side until the minute hand I04of the clock makes contact with terminal H0,

simultaneously with the completion of contact between the hour hand I06and one of the contacts1I08J At such time the leg releasing relay I22closes the associated contacts I50 resulting in the firing of the legreleasing device 48. Releasing of the legs causes the device to assumethe position shown in Figure 6. It should be noted'that heavy legconstruction is an advantage in performing this erecting, particularlywhen the nose member 42 has been more or less flattened by impact withthe earth. The high rotational inertia of the legs about pins 40,articularly those legs not in' contact with the ground, enables them tocarry through to the final erected position when put in motion by theurging action of the springs 44.

. Firing of the leg releasing device 48 causes the closing of theassociated contacts 98 resulting in the energization of the contacts 54of antenna erecting relay I24. At the same time contacts 96 open toprevent the leg releasing relay 22 from ever subsequently drawing powerfrom the relay batter'yII48. It will be apparent from an inspection of'the wiring diagram in Figure 2 that the. relay I46 is connected inseries with the relays'I24, I26, I28, and I30, so that energization ofthe relays I24, I26, I28, and I30 by the minute hand I04 through thecontacts II2, H4, H6, H3, and I also energizes the relay I46 to applyfilament power to the several vacuum tubes. Contact between the minutehand I04 and contact II2-next causes erection of the antenna through theaction of the antenna erecting relay I24 and the closing of contacts I54which fires the antenna erecting device 10. At the same time, theclosing of contact I52 switches the reference resistor I64 acrossterminals I66 and I68 leading to the grid circuit of the relaxationoscillator 34. Simultaneously with operation of relay I24 the relay I46closes its associated contacts I44 applying filament power to theoscillator and transmitter portion of the station.

With" the reference resistor I64 in parallel with the .-c'apacitor I10in the grid circuit of the relaxation oscillator 34, the oscillator willproduce pulses at a rate dependent upon the value of the referenceresistor I64. The pulse rate will be approximately two pulses persecond. Pulses of current in the plate circuit of vacuum tube .I.'I2cause interrupted action of the plate relay oflthe. grid. bias resistorof thefcrystal oscillator the transmitter 36. Since the referenceresistor I64 has a fixed resistance, its calibrated pulse rate is knownand in actual operation of the devicemay beused to determine whether theassociated relaxation oscillator circuit is still in calibration. Theoperation of the oscillator and use of the reference resistor isdescribed in greater detail in the patent application ofLowell et al.mentioned above.

Following transmission of the reference pulses, the minute hand I04moves away from terminal II2 removing the reference resistor I64 fromthe circuit and moves into contact with terminal I I4 closing thepressure-responsive relay I26. Closing of the latter relay causes thecircuit to be made through contacts I56 to apply the resistor I32 acrossterminals I66 and I68. At the same time the circuit is completed throughcontacts I58 causing operation of the clamping device I34 which, asstated above, is efiective to reduce contact resistance between themoving elements of the variable resistor I32. .The use of a clampingdevice is old in the art and will not be discussed in detail. Withpressure-responsive resistor I32 in the circuit of the relaxationoscillator 34 the transmitter will transmit pulses at a rate dependentupon the existing resistance of this resistor. The pulse rate isinterpreted at the receiving station in terms of barometric pressure.

Subsequently, the minute hand I04 makes contact with terminal II6 on theclock 30 causing contacts I60 of relay I28 to switch thetemperature-responsive resistor I36 across terminals I66 and I68. Thisproduces a transmitted pulse rate dependent upon the temperatureexisting at the device at the time of transmission. Next, the making ofa circuit at terminal II8 of the clock through the action of relay I30and contacts I62 switches the humidity-responsive resistor I38 into thecircuit of the relaxation oscillator 34. A clamping magnet I40 operatedin the same manner as discussed in connection with the clamping deviceI34 is energized through the contacts I63 on relay I30.

Finally, the reference resistor I64 is again cut into the relaxationoscillator circuit bymeans of terminal I20 of the clock 30. Uponcompletion of the transmitting sequence just described, the

' to one skilled in the art that the program can 11.6. whichperiodically shorts out portion I80 be changed to suit the specificrequirements by proper spacing of terminals IIO through I20. It willalso be obvious to one skilled in the art that other information inaddition to pressure, temperature and humidity may be included in theprogram by the addition of clock contacts, relays and acondition-responsive resistor similarly connected.

It will be seen from above that a weather station constructed inaccordance with my teach.- ings will enable impact to be absorbed bydeformation of the light nose portion while the construction of theantenna mountingand the erecting device is such as to enable effectiveerection and reliable transmission in spite of the deformation occurringin the nose portion. It

will also be seen that I have provided an interlocked switching systemwhich insures proper sequence of the erecting and transmitting functionsregardless of the time indicated by the clock at the time the weatherstation is dropped.

When the station is to be used only as a beacon, the radio transmitterand its control mechanism may be simplified merely to transmit a signalwhich may be used to guide, for example,

7 other craft equipped with radio director-finding apparatus.

While I have shown and described but one embodiment of my invention, itwill appear to those skilled in the art that various changes andmodifications may be made without departing from my invention, and I,therefore, aim in the appended claims to cover all such changes andmodifications as fall Within the true scope of my invention.

What I claim as nev. and desire to secure by Letters Patentv of theUnited States is:

1. A portable radio transmitting station designed to be dropped fromaircraft comprising a bombl ike housing, a light gauge deformable convexnose on said housing, a radio transmitter including a telescopingantenna operated by gas pressure, an antenna barrel housing saidantenna, said antenna barrel being slidably mounted in alignmentdetermining apertures in said housing and extending into proximity withthe inner surface of said nose, a rigidly-mounted gas reservoir withinsaid housing, a flexible connection between said reservoir and saidantenna barrel, whereby axial translation of said antenna barrelupo-ninward deformation of said nose portion is permitted and the likelihoodof damage to said antenna upon impact with the earth is reduced.

2. A portable radio transmitting station designed to be dropped fromaircraft comprising a bomblike housing, a light gauge deformable convexnose on said housing, the center of gravity of said station located nearsaid nose, legs for the erection and support of said housing, said legsbeing hingedly attached about the waist of said housin at a level abovesaid center of gravity and each arranged to swing in a plane whichincludes the axis of said housing, retaining means to hold said legsalong said housing in a direction away from said nose, biasing means tourge said legs toward said nose to erect said housing upon release ofsaid retaining means, said legs being of large rotational inertiawhereby the erection of said housin is facilitated in spite ofdeformation of said nose upon impact with the earth.

3. A portable automatic radio transmitting station designed to bedropped by parachute from aircraft comprising a parachute releasingdevice and erectin devices required to be operated in a predeterminedorder, means initiated upon impact with the earth to operate saidparatchute releasing device, a clock having switch means to cause theoperation of each of said erecting devices in sequence at apredetermined true time, normally open interlock switches operated bysaid parachute releasing device and each of said erecting devicesrespectively, said switches bein closed upon operation of the associateddevice, said interlock switches being so connected to said clock switchmeans that the operation of each of said interlock switches isprerequisite to the operation of the erecting device designed to beoperated next in order, whereby said clock is ineffective to operatesaid erecting devices except in the predetermined order regardless ofthe time ind cated by said clock at the time of dropping said station.

4. A portable automatic radio transmitting station designed to bedropped by parachute from aircraft comprising a parachute releasingdevice, erecting devices and a transmitting de vice required to beoperated in a predetermined order, means initiated upon impact with theearth to operate said parachute releasing device, a clock having switchmeans to cause the operation of each of said erecting devices and saidtransmittin device in sequence at a predetermined true time, normallyopen interlock switches operated by said parachute releasin device andeach of said erecting devices respectively, said switches being closeddue to operation of the assoc-iated device, said interlock switchesbeing so connected to said clock switch means that the operation of eachof said interlock switches is prerequisite to the operation of theerecting device designed to be operated next in order, whereby saidparachute releasing device and each of said erecting devices operatesonly in a predetermined order and whereby all erecting functions areperformed before energization of said transmitting device regardless ofthe time indicated by said clock at the time of dropping said station.

5. A radio station as claimed in claim 4 including an arming switchoperated upon dropping of said station from aircraft, said arming switchbeing effective before it is operated to prevent said clock switch meansfrom energizing said erectin devices or said transmitting device.

6. A portable radio transmitting station designed to be dropped byparachute from'aircraft comprising a bomb-like housing, an erectingdevice controlled by an erecting device interlock switch, a parachutereleasin device, means effective upon contact of said station and theearth to operate said releasing device, said parachute releasing deviceincluding a dowel pin adapted to be axially translated to perform thereleasing function, an erecting device interlock switch comprising aspring biased operating plunger, said plunger being positioned to moveinto the space normally occupied by said dowel pin to operate saidinterlock switch, whereby closing of said interlock switch andoperation'of said erecting device is not possible until ejection of saiddowel pin.

'7. An air-launched radio transmitting section comprising a parachute,an extensible antenna, a radio transmitter, a time-controlled switch fordetermining the periods of energization of said transmitter, andelectrical control system comprising switch gear responsive to impactwith earth for controlling release of said parachute, extension of saidantenna and functioning of said time-controlled switch, and interlockswitches included in said system t ensure'release of said parachute andextension of said antenna in predetermined sequence.

ROBERT P. BENNETT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Arenstein Feb. 21, 1950

